Double-superphosphate manufacture



the strength Patented Nov. 4, 1930 UNITED STATES WILLIAM BARKLEY xI e, ECOLUMBIA,

' TII-I/ZER wonxs, 0E CHICAGO, ILLINOIS,

P ENT oFFIcE TENNESSEE, nssreNon r0 maroon Em:- A CORPORATION ON NEWJERSEY I DOUBLE-SUPERPHOSPHATE MANUFA CTUBE No Drawing.

My presentinvention relates to improve moms in the process or method ofproducmg double superphosphate set forth in tion of heat andconsummating such chemical reaction by the application of heat andsimultaneously'drying the slurry to a solid roduct b such heat, theheating operation eing per ormed, preferably, by running'the'slurry-continuously into and throu h an inment. 1 l have discoveredthataproduct of better hysical condition, containing less insolubleclined, rotary, direct-heat,'cylindr1cal drier concurrently with thecombustion gases with which the agitated slurry is direct.

contact, the solid discharged product being in condition for immediatedisintegration and thenc'onveyance to storage or for ship- 0 andresulting in asomewhat better yieldfrom the rock employed, can be made,

if the, slurry is not immediately'dried to a solid condition asdischarged from the drier,

but is allowed to flow from the latter, at a temperature ofapproximately 180 Fahrenheit to- 250 Fahrenheit, ina' thick liquid.

condition into a pit orother suitable sta tionary or movable container.I

, On standing in the pit, the mass sets up rapidl to asolid condition,so that, at the end 0 from about 24hours'to 72 hours, it

can be readily removed by spading or by any suitable mechanical meanssuch as a grab-bucket.

v The solid so produced in the pitcontains between 10% 150309;.moisture, and, consequently, it is advisable and desirableto pass itthrough some sort of'a drier to reduce the moisture well under 10% withcorresponding grade increase of the final product.

5 The new and improved process as at pres- Application filed January 6,1980. Seriallio. 418,999.

ent actually commercially practised is substantially as follows;

Finely ground commercial phosphaterock is added to crude phosphoric acidsolution, containing about 16% to 20% P 0? the ratio being approximatelyone pound 0 ground rock to each pound of P 0 in'solu tion, the slurry soproduced being run through-a direct-heat drier, heated with acoal flame,concurrently with the combustion gases, wherebya large part of thechemical reaction occurs in the drier and a very considerable percentageof the water is eva orated'or driven oil. v

he process is so governed or controlled, however, that the materialundergoing treatment is discharged or delivered from the drier as athick li uid, at a temperature of about 220 Fahren eit and containinganywhere from 10%.to 30%. water, into a. pit

Where-it sets into a rather orous solid, the j chemical reaction in suchpit.

probably eing completed After the expiration of anywhere from 1about--24 hours to approximately 72 hours, such set or solidifiedmaterial, containing from' about10% to 25% moisture, is dug out of thepit, either by hand or by the use of a mechanically-operatedgrab-bucket, and .is piled up for re-handling' througha drier orconveyed dir'ectl into the charging end of a small, directeat drier intothe hot gases travelling in the same direct on as such charge. a k p Inthis drier,v the moisture content of the product is not only madesubstantially umabout 3% to 9% and the discharged product is conveyed tostorage and upon dis1ntegra-,- tion is ready for shipment to the trade.

Such small or second drier maybe economically heated by the waste'heatgases of the first'or' larger drier, or it may be heated by a low coalor oil fire. I

As an alternative, the thick liquid may be run direct from the drier toa movable container which when loaded/may be wheeled I .from thedischarge opening allowed to stand until theliquid is set and t enmoved'to the feed end of the secondary drier into the feed "form butis-reduced to somewhere between ground phosphate-rock and dilutephosphoric I acid solution, concentrating said slurry by heat to a thickliquid only, allowing such liquid to set to a solid condition aftertermination of said heating action, and drying said solid material.

2. The process of producing double superphosphate, consisting in forminga slur by addin ground phosphaterock to. a dilute phosphoric acidsolution of a strength insufficient to efit'ect complete reaction withthe rock without the application of heat, heating such slurry tofacilitate chemical reaction between 5. The process ofproducingdoublesuperphosphate, consisting in forming a'slurry by adding groundphosphate-rock to a dilute phosphoric acid solution of a strengthinsuflicient to effect complete reaction with the rock without theapplication of heat, passing such slurry through a direct-heat drierconcurrently with its combustion gases to facilitate the chemicalreaction between the constituents of the slurry and simultaneously toconcentrate the slurry to a thick liquid only, discharging such thickliquid from the drier, allowing it to set to a solid condition, dryingsuch solid material by passing it through a direct-heat drierconcurrently with the hot gases thereof and heating said second drier bythe waste heat gases from said first drier.

In witness whereof I have hereunto set my hand.

WILLIAM BARKLEY KING.

its constituents and simultaneously to concentrate the slurry to a thickliquid only,

solidifying such liquid under normal atmospheric temperature aftertermination of said heating, the application of heat thereto.

8. The process of producing double superphosphate, consisting in forminga slurry by adding ground phosphate-rock to a dilute phosphoric acidsolution containing between and drying such solid material by about 16%to 20% P 0 about one pound of such ground rock being used for everypound of P 0 in solution, heating such slurry to facilitate chemicalreaction between its constituents and simultaneously to concentrate theslurry to a thick liquid only, allowing suchliquid to set to a solidcondition for from about 24 hours to 72 hours under nor- -malatmospheric temperature after-termination of such heating, and dryingsuch solid material by the application of heat thereto to reduce itsmoisture content to about"3% to 9%.

t 'lihe process of producing double superate, consisting in forming aslurry by addin ground phosphate-rock to a d1lute phosphoric acidsolution of a strength insufiicient rock without the application ofheat, passing suchslurry through a direct-heat drier concurrently withits combustion gases to facilitate the chemical reaction between theconstituents of the slurry and simultaneously to concentrate the slurryto a thick liquid only, solidifying the discharged thickliquid, anddrying such solid material by passing it througli'aheat drier.

to efiectcomplete reaction with the i

